This invention relates to a door closer, more specifically to a door closer with semi-automatic latching to hold a door open.
A door closer is an apparatus to return an opened door to a closed position. Common door closers comprise a cylinder having an end attachable to a door or door frame. The cylinder contains a piston on a rod with an end extending from the free end of the cylinder. The extending end of the rod is attachable to a door frame or door. A spring in the cylinder urges the piston to return to a maximum retracted position in the cylinder.
Usually a manually operated latch such as a cantable washer is mounted on the exposed part of the rod to allow a user to arrest the door temporarily in an open position. Such a latch is not very convenient to a user. Its operation normally requires two hands, one being used to open and hold the door while the other is used to slide the washer on the rod until it contacts a stop provided on the cylinder. Upon release of the door, the stop cants the washer so that it grasps and arrests the rod and the door is held open. To unlatch the door, the user must open the door further to relieve the force on the washer applied by the stop and then slide the washer along the rod to a location where it will not contact the stop for the entire retracting movement of the rod into the cylinder as the door closes.
Door closers with more convenient latches have been proposed in the prior art, but have not gained commercial acceptance. The reasons are that they are considerably more expensive than closers with manual latching as described and each have particular drawbacks peculiar to the mechanism employed. What is needed is a door closer which is inexpensive, reliable, durable and more convenient to latch and unlatch than existing door closers with conventional manually operated latches. This invention satisfies the above needs.